1. Field of the Invention
The invention provides a process for producing epoxyorganoalkoxysilanes through a rhodium catalyzed hydrosilation of ethylenically unsaturated epoxides with alkoxysilanes in the presence of nitroqenous impurities.
2. Description of the Prior Art
The hydrosilation reaction was discovered in 1947 and over the years has become one of the best known and most widely practiced reactions in organosilicon chemistry. Hydrosilations are used in a wide variety of large scale commercial applications and have been the subject of several extensive reviews, i.e., Organic Insertion Reactions of Group II Elements, Consultants Bureau, N.Y., 1966; Orqanometallic Compounds of the Group IV Elements, Dekker, N.Y., 1968, Vol. I; Preparation of Carbofunctional Orqanosilanes by an Addition Reaction, Moscow, 1971; Russ Chem Rev., 46, 264 (1977); and J. Organometal Chem. Library 5, 1977, pp. 1-179.
Various transition metals are known to be effective as catalysts for the hydrosilation reaction. U.S. Pat. No. 2,823,218 teaches that chloroplatinic acid, a soluble form of platinum is a particularly effective hydrosilation catalyst. The reaction of unsaturated epoxides and alkoxysilanes provides a direct process for producing various epoxyorganofunctional alkoxysilanes. The platinum catalyzed addition of allyl glycidyl ether and 1,2-epoxy-4-vinylcyclohexane to alkoxysilanes offers a direct route to the corresponding silyl substituted epoxides. ##STR1##
This reaction is well known and has been studied by many investigators, for example: Ger. Offen. No. 1,937,904; Japan No. 75 24,947; and Kremniiorg. Soedin., Tr. Soveshch. 1967, No. 3, 1982.
However, platinum catalyzed hydrosilations are often severely inhibited when nitrogenous impurities are present in either the reacting silane or olefin. In particular, hydrosilations where the olefin is an ethylenically unsaturated epoxide and the silane is an alkoxysilane are especially sensitive to the presence of nitrogenous impurities. For this reaction to be viable, the reactants must be extensively refined to remove nitrogenous impurities prior to the reaction.